Thanks for posting this excellent question.
Yes there is some guidance here for that. Also guidance for the entire process of upgrading from Lx 4.1 to Lx 4.2.
If you accept the default for everything you will end up with the old mirror.list instead of Mirrorbits which is a notable improvement. That is why I suggest to accept the new files for all the .repo files. If you accept the default for grub you may miss changes in how grub boots newer kernels so also it is recommenced to accept the new file for grub. Otherwise for the rest the default is good.
Note: Accepting the default for everything works as far as I know. I am just suggesting there is a better path.
Note-2: I accept that I should have explained this in more detail in the other post.